All the anecdotes say that the condensation reaction between nitrothane and benzaldehyde

requires a alkylamine catalyst to work, but we wanted to put this to the test to see if

using plain old potassium hydroxide would work.

We started by weighing out 5 grams of nitrothane into a 100 ml flask as you can see here.

We then placed a small magnetic stir bar in the flask.

We then weighed out 7 grams of benzaldehyde.

This is slightly yellow colored, but fairly pure.

We made this in our previous video.

The reagents we used in this reaction are dry, but we didn't make any special effort

to exclude moisture.

We measured out 5 mL of methanol, and added this to the benzaldehyde to act as a solvent

for the reaction.

Then we added this mixture to the reaction flask containing the nitrothane.

At this point you can see that no change or reaction was visible.

This condensation reaction needs a catalyst to work.

The literature suggests using an organic amine, but we wanted to try potassium hydroxide as

a base.

So we measured out 4 grams of potassium hydroxide, and then measured out 10 mL of methanol as

our solvent.

Potassium hydroxide is quite soluble.

But it takes quite a lot of stirring and swirling to get it all into solution.

In addition, the mixture heats up quite a bit, so this step takes a little while.

Nearly there.

Once dissolved we chilled this down to 0 degrees C in the freezer.

Now we want to do the reaction in the cold.

So we prepared a bowl containing some water and a magnetic stir bar.

And added lots of ice.

And then we added a little bit of water.

Then we added salt to help get the temperature down.

We placed the reaction flask in the ice bath and switched on stirring, then allowed this

to cool right down for a few minutes.

We placed a thermometer in the ice so we could monitor the temperature.

The idea was to keep the reaction below zero.

Here's our chilled and quite viscous potassium hydroxide.

We set up a dropper so we could add this slowly drop wise.

Everything's ready.

So let's add a few drops of the base solution.

The color is very slowly becoming slightly more yellow.

This is a good sign as our product should be a yellow color.

We'll slowly add some more of the base.

Again, a very slight color darkening.

We added the rest of the methanolic potassium hydroxide solution over about 20 minutes with

constant stirring.

At the end we left the mixture stirring on the ice bath for an hour.

After which the water bath temperature was still 0 degrees C.

After an hour we allowed the mixture to warm to around 10 degrees C keeping stirring going.

The fruity aroma of nitroethane has gone, but there's still a strong almond-like aroma

of benzaldehyde.

But the color is encouraging.

We measured out 10 mils of concentrated hydrochloric acid, sufficient to neutralize all the base.

And we mixed this with 10 mils of water to create a dilute solution.

We chilled this down to 0 degrees for the next step.

We slowly added the chilled acid to the reaction mixture.

As you can see, a white precipitate assumed to be an inorganic salt was produced.

We continued adding the chilled acid and the temperature rose to around 20 degrees.

At this point a lot of salt had precipitated.

So we added just a little bit more.

Just enough water to get this into solution.

And a yellow bottom layer appeared.

We tested the pH of the mixture and made sure it was acidic.

The layer separated well as you can see.

This is probably our product dissolved in unreacted benzaldehyde.

So we used a pipette to get this out of the flask.

And placed this into a petri dish.

First we added the salt.

First we wanted to see if this liquid would crystallize.

So we placed this in the freezer overnight.

It became a bit more viscous in consistency, but no crystals formed.

The yellow liquid had a very slight aroma of the product, which has a slightly lacrimatory

irritating effect, but mostly smelt strongly of benzaldehyde.

Sometimes these compounds can crystallize when in contact with ice.

So we poured the liquid onto a few cubes of ice in a beaker.

We agitated the mixture and then allowed it to rest for several hours.

As you can see, the yellow oil is slightly denser than water and sinks to the bottom.

Again, no crystals formed.

And the crystallization occurred.

We also tried separating and drying the liquid carefully, then freezing again.

No crystals.

We think there's a small amount of product in here.

And the slightly irritating effect of the vapors when the oil is warmed indicate this.

However what we have here is mostly unreacted benzaldehyde.

And it looks like our product forms a very happy stable solution in the benzaldehyde and

since there's only a small amount of it.

Can't be separated.

It might be possible to separate using column chromatography, but we're not set up for this.

And it's probably not worth it.

So we consider this me-busted.

To condense nitrothane and benzaldehyde you can use a regular alkali metal hydroxide in

alcoholic solution.

You have to use an alkalamine catalyst.

Or perhaps ammonium acetate in a syringe.

acid as in our other video using vanillin as the aldehyde.

So don't waste your precious reagents.

Thanks for watching.